With the digitalization of printing data, there has been demand for CTP technology which is low in cost, easy to handle and is as suited for printing as the PS plate. There are many kinds of printing plate supports which are used in CTP, but those using a plastic film support have become known for convenience in handling and carrying the printing plate (for example see Patent Document 1).
These days, much is expected of process-free plates which do not require development processing using a special chemical. The majority of the process-free plates are the thermal type which performs image formation using infrared laser exposure. The thermal type printing plate material is largely divided into the ablation type and printing device development type, but the printing device development type is preferable in view of device cost and the like.
Furthermore, the printing plate material which is wound up in the form of a roll is favorable in view of the plate material cost, but there is the problem that the back layer of the image forming layer which is matted may become damaged and printing device development properties are reduced as print smearing is caused.
Furthermore, when the matting agents are overconcentration in a particular area of the back layer the development properties are reduced.
The present invention was conceived in view of solving this problem.
[Patent Document 1] Japanese Patent Application Laid-Open No. 2000-258899 publication